1 /*
2 * Copyright 2021 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "include/core/SkBlendMode.h"
9 #include "include/core/SkCanvas.h"
10 #include "include/core/SkMatrix.h"
11 #include "include/core/SkPaint.h"
12 #include "include/core/SkPicture.h"
13 #include "include/core/SkPictureRecorder.h"
14 #include "include/core/SkPoint.h"
15 #include "include/core/SkRect.h"
16 #include "include/core/SkRefCnt.h"
17 #include "include/core/SkSamplingOptions.h"
18 #include "include/core/SkShader.h"
19 #include "include/core/SkSize.h"
20 #include "include/core/SkString.h"
21 #include "include/core/SkTileMode.h"
22 #include "include/effects/SkRuntimeEffect.h"
23 #include "include/private/base/SkAssert.h"
24 #include "modules/skottie/src/Adapter.h"
25 #include "modules/skottie/src/SkottiePriv.h"
26 #include "modules/skottie/src/SkottieValue.h"
27 #include "modules/skottie/src/effects/Effects.h"
28 #include "modules/sksg/include/SkSGNode.h"
29 #include "modules/sksg/include/SkSGRenderNode.h"
30
31 #include <cmath>
32 #include <cstddef>
33 #include <utility>
34 #include <vector>
35
36 namespace skjson {
37 class ArrayValue;
38 }
39 namespace sksg {
40 class InvalidationController;
41 }
42
43 namespace skottie::internal {
44 namespace {
45
46 static constexpr char gBulgeDisplacementSkSL[] =
47 "uniform shader u_layer;"
48
49 "uniform float2 u_center;"
50 "uniform float2 u_radius;"
51 "uniform float2 u_radius_inv;"
52 "uniform float u_h;"
53 "uniform float u_rcpR;"
54 "uniform float u_rcpAsinInvR;"
55 "uniform float u_selector;"
56
57 // AE's bulge effect appears to be a combination of spherical displacement and
58 // exponential displacement along the radius.
59 // To simplify the math, we pre scale/translate such that the ellipse becomes a
60 // circle with radius == 1, centered on origin.
61 "float2 displace_sph(float2 v) {"
62 "float arc_ratio = asin(length(v)*u_rcpR)*u_rcpAsinInvR;"
63 "return normalize(v)*arc_ratio - v;"
64 "}"
65
66 "float2 displace_exp(float2 v) {"
67 "return v*pow(dot(v,v),u_h) - v;"
68 "}"
69
70 "half2 displace(float2 v) {"
71 "float t = dot(v, v);"
72 "if (t >= 1) {"
73 "return v;"
74 "}"
75 "float2 d = displace_sph(v) + displace_exp(v);"
76 "return v + (d * u_selector);"
77 "}"
78
79 "half4 main(float2 xy) {"
80 // This normalization used to be handled externally, via a local matrix, but that started
81 // clashing with picture shader's tile sizing logic.
82 // TODO: investigate other ways to manage picture-shader's tile allocation.
83 "xy = (xy - u_center)*u_radius_inv;"
84
85 "xy = displace(xy);"
86 "xy = xy*u_radius + u_center;"
87 "return u_layer.eval(xy);"
88 "}";
89
bulge_effect()90 static sk_sp<SkRuntimeEffect> bulge_effect() {
91 static const SkRuntimeEffect* effect =
92 SkRuntimeEffect::MakeForShader(SkString(gBulgeDisplacementSkSL), {}).effect.release();
93 SkASSERT(effect);
94
95 return sk_ref_sp(effect);
96 }
97
98 class BulgeNode final : public sksg::CustomRenderNode {
99 public:
BulgeNode(sk_sp<RenderNode> child,const SkSize & child_size)100 explicit BulgeNode(sk_sp<RenderNode> child, const SkSize& child_size)
101 : INHERITED({std::move(child)})
102 , fChildSize(child_size) {}
103
104 SG_ATTRIBUTE(Center , SkPoint , fCenter)
105 SG_ATTRIBUTE(Radius , SkVector , fRadius)
106 SG_ATTRIBUTE(Height , float , fHeight)
107
108 private:
contentShader()109 sk_sp<SkShader> contentShader() {
110 if (!fContentShader || this->hasChildrenInval()) {
111 const auto& child = this->children()[0];
112 child->revalidate(nullptr, SkMatrix::I());
113
114 SkPictureRecorder recorder;
115 child->render(recorder.beginRecording(SkRect::MakeSize(fChildSize)));
116
117 fContentShader = recorder.finishRecordingAsPicture()
118 ->makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat, SkFilterMode::kLinear,
119 nullptr, nullptr);
120 }
121
122 return fContentShader;
123 }
124
buildEffectShader()125 sk_sp<SkShader> buildEffectShader() {
126 if (fHeight == 0) {
127 return nullptr;
128 }
129
130 SkRuntimeShaderBuilder builder(bulge_effect());
131 float adjHeight = std::abs(fHeight)/4;
132 float r = (1 + adjHeight)/2/sqrt(adjHeight);
133 float h = std::pow(adjHeight, 3)*1.3;
134 builder.uniform("u_center") = fCenter;
135 builder.uniform("u_radius") = fRadius;
136 builder.uniform("u_radius_inv") = SkVector{1/fRadius.fX, 1/fRadius.fY};
137 builder.uniform("u_h") = h;
138 builder.uniform("u_rcpR") = 1.0f/r;
139 builder.uniform("u_rcpAsinInvR") = 1.0f/std::asin(1/r);
140 builder.uniform("u_selector") = (fHeight > 0 ? 1.0f : -1.0f);
141
142 builder.child("u_layer") = this->contentShader();
143
144 return builder.makeShader();
145 }
146
onRevalidate(sksg::InvalidationController * ic,const SkMatrix & ctm)147 SkRect onRevalidate(sksg::InvalidationController* ic, const SkMatrix& ctm) override {
148 const auto& child = this->children()[0];
149 fEffectShader = buildEffectShader();
150 return child->revalidate(ic, ctm);
151 }
152
onRender(SkCanvas * canvas,const RenderContext * ctx) const153 void onRender(SkCanvas* canvas, const RenderContext* ctx) const override {
154 if (fHeight == 0) {
155 this->children()[0]->render(canvas, ctx);
156 return;
157 }
158 const auto& bounds = this->bounds();
159 const auto local_ctx = ScopedRenderContext(canvas, ctx)
160 .setIsolation(bounds, canvas->getTotalMatrix(), true);
161
162 canvas->saveLayer(&bounds, nullptr);
163
164 SkPaint effect_paint;
165 effect_paint.setShader(fEffectShader);
166 effect_paint.setBlendMode(SkBlendMode::kSrcOver);
167
168 canvas->drawPaint(effect_paint);
169 }
170
onNodeAt(const SkPoint &) const171 const RenderNode* onNodeAt(const SkPoint&) const override { return nullptr; } // no hit-testing
172
173 sk_sp<SkShader> fEffectShader;
174 sk_sp<SkShader> fContentShader;
175 const SkSize fChildSize;
176
177 SkPoint fCenter = {0,0};
178 SkVector fRadius = {0,0};
179 float fHeight = 0;
180
181 using INHERITED = sksg::CustomRenderNode;
182 };
183
184 class BulgeEffectAdapter final : public DiscardableAdapterBase<BulgeEffectAdapter,
185 BulgeNode> {
186 public:
BulgeEffectAdapter(const skjson::ArrayValue & jprops,const AnimationBuilder & abuilder,sk_sp<BulgeNode> node)187 BulgeEffectAdapter(const skjson::ArrayValue& jprops,
188 const AnimationBuilder& abuilder,
189 sk_sp<BulgeNode> node)
190 : INHERITED(std::move(node))
191 {
192 enum : size_t {
193 kHorizontalRadius_Index = 0,
194 kVerticalRadius_Index = 1,
195 kBulgeCenter_Index = 2,
196 kBulgeHeight_Index = 3,
197 // kTaper_Index = 4,
198 // kAA_Index = 5,
199 // kPinning_Index = 6,
200 };
201 EffectBinder(jprops, abuilder, this).bind(kHorizontalRadius_Index, fHorizontalRadius)
202 .bind(kVerticalRadius_Index, fVerticalRadius)
203 .bind(kBulgeCenter_Index, fCenter)
204 .bind(kBulgeHeight_Index, fBulgeHeight);
205 }
206
207 private:
onSync()208 void onSync() override {
209 // pre-shader math
210 auto n = this->node();
211 n->setCenter({fCenter.x, fCenter.y});
212 n->setRadius({fHorizontalRadius, fVerticalRadius});
213 n->setHeight(fBulgeHeight);
214 }
215
216 Vec2Value fCenter;
217 ScalarValue fHorizontalRadius,
218 fVerticalRadius,
219 fBulgeHeight;
220 using INHERITED = DiscardableAdapterBase<BulgeEffectAdapter, BulgeNode>;
221 };
222
223 } // namespace
224
attachBulgeEffect(const skjson::ArrayValue & jprops,sk_sp<sksg::RenderNode> layer) const225 sk_sp<sksg::RenderNode> EffectBuilder::attachBulgeEffect(const skjson::ArrayValue& jprops,
226 sk_sp<sksg::RenderNode> layer) const {
227 auto shaderNode = sk_make_sp<BulgeNode>(std::move(layer), fLayerSize);
228 return fBuilder->attachDiscardableAdapter<BulgeEffectAdapter>(jprops, *fBuilder,
229 std::move(shaderNode));
230 }
231
232 } // namespace skottie::internal
233